Remote-control device



Dec. l2, 1950 R. P. DICE ETAL mom-CONTROL DEVICE Filed oct. 12, 1949 Q'TTOR EY Patented Dec. 12, 1950 UNITED STATES GFFICE 2,534,110 REMOTE-CONTROL DEVICE Robert P. Dice, WebsterSprings, and Brooks H. Keener, Bergoo, W. Va. Application October 12, 1949, Serial No. 120,928 6 Claims. (C1. 19a-203) This invention relates to remote control devices for electrically driven apparatus adapted to be activated by magnetic relays, and more particularly to an electrical switch control arrangement for belt conveyors or the like.

Heavy duty conveyor belts, of the character uesd for transportation of material, and personnel, are usually continuously driven from a single power source, for example, an electric motor, having magnetic relays associated therewith, whereby actuation of the motor may be controlled from a point remote therefrom. The belts are of appreciable length, in some instances three or four thousand feet long, and from a practical operational standpoint, control means must of necessity be provided at spaced points along .the path of travel of the belt, so that the belt may be stopped or started, as desired, .at points remote from the power source, to permit loadingor unloading material, and for personnel.

Heretofore, it has been suggested to eiect remote control of conveyor belts of the abovementioned type by means of push .button .control stationsror pull-outswitches `located at spaced points along the path of travel of the belt. While the prior suggested remote control arrangements are satisfactory to eiect control from` a plurality of predetermined locations Vlengthwise ofthe belt, they are open to the objection that they .do not permit continuous control, that is `to say, control of the conveyor belt from any .point along its travel.

Belt -conveyors are particularly adaptable for use in coal mining operations by reasorrof their sturdy performance, under heavy loads, and the fact that such conveyors can be installed and operated in mine passageways of comparatively small clearances. Specialproblems-o safety are encountered in subterranean work, such -as coal mines, vwhere the --belts are used to transport personnel and tools, aswell as coal. Because of the dangers inc-ident to the A.transportation of personnel on conveyor belts, stringent safety regulations arein force in'various mining-areas, which require, among other things, that thevbelt be equipped with a continuous switch control whereby the belt may be stopped `orstartedat any time by a person riding thereon. -In other Words, according to coal mningregulations presently effective in certain mining areas, positive control of the conveyor belt must be provided for each linear footoffthe conveyor travel.

`After ,considerable research and experimentation, we have foundthat .the dencienciesof conventional spaced control `switch arrangements, with respect to continuous con-trol as required by present mining reglllatifllh'i,` can be Aovercome byrproviding Aa threewire continuous switchinstallation along the entire course Y,of travel `of the belt conveyor.

An object of our invention is tohprovideannimproved `.continuous Aswitch vcontrol u arrangement for conveyorbelts. A Y Y Y `Another object of our inventionis. to vf, provide 2 an improved )continunus` switch system of low voltage, for the control of the motor used to drive'a conveyor belt, whereby to permit substantially instantaneous stopping, starting, and reversal of the direction of travel of the belt at any time, by any person riding the belt. Y

Yet another object of our invention is to provide a continuous, bare wire, overhead switch installation, powered from a low voltage source, and designed to operate differential, low voltage relays, whereby to energize and control the motor used to drive a conveyor belt, from any point along the path of travel of the belt.

Still Vanother object of our invention is to provide a three-wire continuous overhead switch installation, extending above or to one sideof the conveyor belt along its entire course or travel, the wires being connected to a diierential relay adapted to be energized lby .bridging or apposing the central wire with either of the two side wires, whereby to control the motor used to drivefthe ben.

A further object ofcur invention is to provide a central system in which the relay switching mechanisms areseverally mounted in a cabinet, desirably associated with the motor control cabinet whereby the only exposed lines which can be contacted by personnel riding Aon the conveyor beltare the low voltage wires, forming the continuous switch, which can be grasped by the hand and apposed to effect contact and switching control, or the wires may be bridged by a jumper, tool, or other conductive device.

With these and other objects in View, which may be incident to our improvements, the invention consists in the parts and combinations to be hereinafter `set forth and claimed, with the understanding that the several necessary elements comprising our invention may be varied in construction, proportions and arrangements, without departing from the spirit and scope of the appended claims.

In order to make our invention more clearly understood, we have shown in the accompanying drawings means for carrying the same into practical eii'ect, without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In the drawings:

Figure lis a schematic wiring diagram of the novel control system herein;

Fig, 2 is a detail schematic showing of a linepowered low voltage source, and

Fig. 3 is a schematic view, in broken section, of Aa conveyor belt mounted in a mine seam.

' Referring to the drawings, and more particularly to Fig. 3, there is shown a continuous conveyorbelt I, mounted on drive rollers 2, 3, rotatably supported on members a, adapted to rest on the floor 4 of amine. Suitable insulators 5 are secured 4to the mine roof i5, and support the bare wires of thercontinuous switch installation, designated generally by the numeral l0,

Referring now to Fig. 1, the continuous switch installation Ii! will be seen to comprise a center positive wire il, a lateral, forward control wire I2, and a second lateral reverse control wire I3. The positive wire II is connected to the positive pole I4 of a low voltage D. C. battery l5, while the lateral wires I2, I3 are connected to negative pole I of the battery through a common line I'I, and a differential relay designated generally by the numeral 20. the low voltage battery may be replaced by connecting the wires Il and I1 to the variable and fixed taps, respectively, of a voltage-dropping resistor appropriately connected to the 250 volt D. C. supply, which will be discussed more in detail hereinafter.

The differential relay 2u is comprised of a forward coil a and a reverse coil 25h. rFhese coils are provided with a common output 23 connected to return line Il, and separate input leads 2i, and 22, severally connected to switch wires I2 and I5. rihe high-power side of the relay comprises a conductive armature 2li, pivotally mounted as at 25, in conductive relation with an input line tI of a 250 volt D. C. supply, designated generally by the numeral Sii, having a return line 52. rllhe armature which is normally biased to neutral position, carries forward contacts 26, 2l and reverse contacts 28. 29. The contacts and 28 are severally adapted to respectively engage forward contact 5I and reverse contact 42 of a differential relay 40.

The relay du is composed of armature 55, a forward coil 43 and a reverse coil lili, severally connected through input lines 45, 45, to contacts 25 and 28 of differential relay 25. The return leads 4l', it of the coils 4t, are connected through ground feeder wire da to the 250 volt D. C. return line 52. The differential relay iii is adapted to control a switch mechanisin 5s having a forward contact 5l, and a reverse contact 52 leading through lines 55, 54, to the forward and reverse controls of the motor starter relays, not shown. The conductive armature is pivoted at and is provided with contacts 5l, 52E, adapted to severally contact motor starter control contacts' I, 52.

A time delay relay to and a ratchet relay 1! comprise the balance system for the electrical actuating members. The relay @il is of the quickshut, slow-open type, and its input @I is connected through bridge to contacts 53, 64, severally apposed by contacts 2l and 2Q, of the differential relay 2li. rEhe output side of coil @u is connected through return leads C55 to the ground feeder wire, or bus bar t5, previously described. The armature is normally biased in the open position, and is pivoted at t'i, being provided with contact 5; is its free end. Lead 59 connects armature with high voltage D'. C. input line The contact G3 of armature of relay is apposable to contact 'il of input lead l2 of a ratchet relay l5, having a return lead 'is connected to ground feeder wire or bus bar 4d. Armature lil of relay T5 is pivoted at i5, and is connected through lead F6 to D. C. input line Its contact il is apposable to iixed contact "I8, which is connected to input lead 5! of armature of differential relay 4t. Armature 55, as noted, functions as the movable switch element of transfer switch 55.

The operation of the system is as follows: Assuming that continuous switch members il and i2 are bridged by a conductive bridging member I8, iiow of current is established from battery As shown in Fig. 2, Q

I5, positive switch wire II, jumper i8, return switch wire i2, input lead 2l of coil 20a, and common line Il. The coil 20a is energized, and armature 24 is attracted toward the relay, with the result that contacts 25 and 5I are apposed, as are contacts 21 and G3. With the closing of these contacts, the 250 volt D. C. power flows through input line tI, armature 2d, contacts 25, di, and line 45, to the forward coil 43 of the differential or transfer relay 40, returning through line il and ground feeder wire 45 to the negative side 32 of the 250 volt D. C. supply. When the coil 43 is energized, armature 55 is attracted toward the differential relay 4D, effecting contact between contacts 5l' and 5I of the forward control line 53. Simultaneously, with the energizing of coil 43, contacts 21 and 63 are apposed, and 250 volt D. C. power flows through input lead tI to the timing relay 55, returning through lead 55 to ground feeder wire i9 and line 32. is attracted, apposing contact 58 to contact 1I, thereby establishing a conductive circuit from 250 volt D. C. input line 53, and connecting line es to the input line 'i2 of the ratchet relay li). This relay has a return line i3, connected to the ground feeder wire 49. When ratchet relay 1i) is energized, armature 'I4 is attracted, apposing contact to contact "I5, Circuit is thereby established between positive feed line 33 of the 250 volt D. C. circuit, and lead 59 of transfer relay its, so that current flows through armature 55, contacts '5l and 5I, and forward control line 53, to the forward motor control mechanism.

When the jumper I is removed, current ceases to flow through coil 25a, deenergizing it, and armature 2d is biased to its neutral position, breaking the 250 volt D. C. forward control circuit, and no current flows through coil 43 of transfer relay 40, nor through timing relay 5ft. Due to the special characteristics oi' the latter, its armature t@ breaks slowly, establishing a gap between contacts t8 and 'i I, thereby deenergizing ratchet relay l5. By reason of the special construction of ratchet relay "I5, its armature 'I4 remains in the circuit closing position, and current will continue to iiow from the positive side of the 25o volt D. C. supply, through line 33, leads "It and 59, and armature 55, to the forward motor control line 53.

When it is desired to reverse the direction of travel of the conveyor belt, the wires II and I3 may be bridged, as shown by the dotted line position of jumper I8. Under these circumstances, current flows from low voltage battery I5 through continuous switch wires II and I3, reverse coil Eiib of the low voltage differential relay 20, and return Il to battery I5. The armature 24 is repelled out of its neutral position towards the reverse side, whereby contact is established between contacts 28, i2, and 29, 64, and the 250 volt D. C. supply line 3l, is thereby connected, through line 45, to the input side of coil 44 of transfer relay 4. Armature 55 is then repelled, and the 250 volt D. C. supply is transferred to the reverse control line 54. Simultaneously with the flow of current through line 3|, armature 24, bridge 62 and input lead 6I to timing relay Si), armature 56 is again attracted, closing the 250 volt D. C. circuit through lines 69 and 12 to the ratchet relay l0. The relay is energized and its armature 14 attracted, closing the circuit from the 250 volt input line 33 to transfer relay armature 55 and reverse control lead line 54.`

It will be seen that with the improvements of When coil 5c is energized, its armature 85 the present invention, `a simple foolproof continnous switch control system for continuous conveyor belts is provided, and which is under immediate and direct control of any person riding the belt at any and all times, and at any and all points along the path of travel of the belt. Further, it will be seen that not only may an individual stop the belt, but may cause it to pursuea forward or reverse direction of travel solely by contacting the appropriate combination of switch wires, whereby, due to the holding action of ratchet relay l, current is caused to flow continuously from the 250 volt D. C. supply to the appropriate side of the motor control relays. It will also be appreciated that the novel control system herein comprises four relay installations, which may be mounted together in a single control cabinet, adjacent to, or as a part of the motor control cabinet, all as indicated generally by the dotted line IUO, and that the only parts of the switch system which are exposed are the continuous switch wires l l, l2, I3, which by the very nature of their installation and mode of operation, are required to be exposed. Under such conditions, personnel are at al1 times in full command of the operation of the belt, from any point along the belt.

It will be further noted that the control arrangement not only permits starting, stopping and reversal of direction of travel of the belt, as desired, in normal operation, but it also provides locked control to prevent accidental movement of the conveyor during loading, unloading, or repair thereof.

While we have shown and described the preferred embodiment of our invention, we wish it to be understood-that we do not conne ourselves to the precise details of construction herein set forth by Way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

What is claimed is:

1. A coal mine belt conveyor control system, comprising in combination, a continuous belt conveyor, electric power means for driving the conveyor, relay control means for controlling the belt conveyor drive, and switch control means for actuating the relay controls, said control a,

means including current sensitive relays, alow voltage D. C. source, and continuous switch means comprising a positive current lead and two return leads, said leads being of bare wire and mounted adjacent the conveyor belt, means connecting the positive lead to the current source, and means connecting the return leads to the current sensitive relays, a common return from the relays to the D. C. source; the said switching means being effective upon bridging of the positive lead and either of the return leads to selectively actuate one of the current sensitive relays, whereby to control the conveyor drive.

2. A safety conveyor belt control system for coal mine conveyor belts, comprising a continuous three-wire switch mounted along thev path of the belt and comprising a positive lead and two return leads, a low voltage power source connected to the said leads, the return leads including current sensitive relays operative to control the belt conveyor drive, the said switch wires being bare and adapted to be apposed by grasping or otherwise bridged by personnel riding the conveyor belt, whereby upon bridging the circuit between the positive lead and either of the return 6 u leads the circuit to the current sensitive relays is closed and the conveyor belt drive is selectively controlled.

3. A low Voltage continuous switch control system and high voltage power drives for coal belt conveyors, comprising a continuous switch mounted along and adjacent the path of .the conveyor belt and comprising three bare wires, including a positive lead and a Pair of return leads, the said switch wires being so mounted as to be grasped and apposed, or otherwise bridged by personnel riding the belt, whereby to eifect contact between the positive lead and either of the return leads and selectively stop the conveyor or start it in either direction.

4. A 1.5 v. D. C. continuous switch control system for 250 v. D. C. power drives for coal belt conveyors, comprising a continuous switch mounted along and adjacent the path of the conveyor belt and comprising three bare wires, including a positive lead and a pair of return leads, the said switch wires being so mounted as to be grasped and apposed, or otherwise bridged by personnel riding the belt, whereby to effect contact between the positive lead and either of the return leads and selectively stop the conveyor or start it in either direction.

5. In a safety switch mechanism for the control of high voltage operating circuits, a continuous switch comprising a bare positive wire and at least one bare return wire, a low voltage D, C. current supply, means conductively connecting the said current supply to the said switch wires, and including at least one current sensitive relay in the return line, and a high voltage D. C. operating circuit including a high voltage current supply and a normally open switching member comprising the armature of the current sensitive relay, whereby when the switch wires are bridged, the relay is energized, the armature switch is closed, and the high voltage operating circuit is energized.

6. Safety switching mechanism for reversible drive, motor-driven conveyor belts having motor g relay controls for forward and reverse control of belt travel, comprising a continuous switch mounted over and above a conveyor belt, said switch comprising three parallel bare wires, a low voltage D. C. current source, means connecting the center switch wire to the positive side of the D. C. supply, a differential relay comprising a pair of current sensitive relays, an input lead to each of the said relays, said leads being severally connected to the other continuous switch wires, a common return from the relays to the D. C. source, means for selectively energizing said relays comprising metallic conductors apposable to the positive switch wire and either of the return switch wires, an electromagnetically responsive armature movable to two separate operating positions by the said relays, high voltage current controls operatively associated with the said armature to selectively establish forward and reverse motor relay control circuits, a high voltage D. C. current supply connected on its positive side to the said armature, whereby when bridging contact is established between the positive switch wire and either of the return switch wires, one of the current sensitive relays is energized and the armature is selectively moved to one of its circuit closing positions.

ROBERT P. DICE. BROOKS H. KEENER.

No references cited. 

